"Recently, a method was found for Windows RT that allowed running unsigned code through a rather clever exploit. This method has now been turned into a full fledged tool by XDA Developers member Netham45. All the details are over in this XDA post, including the download." Super-simple, even a child can do it. A big <3 to XDA.

"Nope, this is a kernel hack, not a UEFI firmeware hack. In other words, you still can't boot unsigned code, you can only run it once the OS is in place. But it's a stepping stone to start attacking the firmware."

It will likely be necessary to flash an unrestricted EFI firmware over top of the restricted one that comes with the device. So it may take a while to reverse engineer but assuming we can find a way to re-flash the firmware from within windows then it will happen.